XM just finished up "IT" today, which was their Encycledia of Pop. They went through over 60 years worth of charted music in chronological order. It took well over a month and spanned all six of the decades stations. I know they've done it before, but this was the first time I listened as an XM subscriber. I only tuned in to the early stuff here and there, but I listened all through the 80's and 90's, which is the music I'm most interested in. It was an eye opening experience and a fun trip down memory lane; it brought about both smiles at the classics and a few groans at the duds. Can't wait till they do it again- good stuff.